(Not Applicable)
The present invention generally relates to an apparatus and a method for reducing radar signature emissions from an aircraft, and more particularly to an improved apparatus and method for minimizing radar signature emissions from an aircraft by utilizing a single cavity and door to enclose all landing gears, bombs, and missiles within its fuselage.
Modern aircrafts such as fighter jets typically share two design considerations to optimize their flying. One such design consideration is the emphasis that components (e.g., landing gears and weapons) carried by these aircrafts should be placed near its center of gravity. For example, weapons such as bombs and missiles are commonly positioned near the aircraft""s center of gravity to the best extent possible such that the flight characteristics do not fluctuate by their deployment. Likewise, the landing gears are also disposed around this proximate area as it facilitates the rotation of the aircraft at fairly low take-off speeds.
The other design consideration that many of these modern aircrafts stresses is the concealment of their carried components therewithin to reduce radar signature emissions and aerodynamic drags. More specifically, exposed landing gears and weapons drastically increase the radar cross section of the aircraft, and hence reflects and/or emits more radar signatures. Further, these exposures tend to be subjected to significant air drags thereby diluting the aircraft""s aerodynamics. Accordingly, as exemplified in FIG. 1, these aircrafts conceal their carried components within their structures, typically in their fuselages, so that their radar signature emissions and aerodynamic drags are improved.
Although such concealment achieves the primary objective of lowering radar signatures and aerodynamic drags, these existing aircrafts nonetheless possess certain deficiencies which detract from their overall utility. Perhaps the greatest deficiency of the existing aircrafts is the use of multiple cavities and/or bays within their fuselages to conceal the landing gears, missiles and bombs. As shown in FIG. 1, the existing aircrafts define numerous cavities (typically seven cavities) to separately contain landing gears, missiles, and bombs therein which are then enclosed by their respective doors. The existence of multiple cavities and matching number of doors appears to be inevitable as only one component is enclosed per cavity and door (best shown in FIG. 1).
However, the existence of multiple cavities and doors greatly undermine the purpose of why the components are concealed in the first place. It should be noted that edges and gaps formed on the aircraft""s structure produces more radar signatures than a smooth and continuous one. In this regard, each cavity-enclosing door includes at least four edges which further form gaps and/or cracks with its respective cavity when closing thereupon.
Because these aircrafts typically require at least seven separate cavities each with their respective door, the number of edges, gaps and cracks formed seems to be overbearing. Each of the door edges, gaps and cracks are capable of reflecting radar signals, not to mention being subjected to air drags to debilitate the aircraft""s aerodynamics. Simply put, these deficiencies make the aircraft more easily detectable by enemy radars, and further contribute to the breakdown of its aerodynamics.
Thus, there has long been a need in the industry, and in the aerospace industry in particular, for an apparatus and a method for minimizing radar signature emissions from an aircraft by mitigating the number of door edges, gaps, and cracks. In this respect, the presently contemplated aircraft utilizes a single cavity and door to enclose all landing gears, air-to-ground bombs, and air-to-air missiles within the fuselage near its center of gravity, which also yields the advantage of further diminishing any aerodynamic drags.
In accordance with the present invention, there is provided an aircraft which can minimize its radar signature emission. Such aircraft comprises a fuselage having a lower fuselage portion. An internal fuselage cavity is defined within the lower fuselage portion and contains all landing gears and bombs therein. Moreover, a cavity-enclosing door is engaged to the lower fuselage portion. This specific cavity-enclosing door may form a stowed position relative to the internal fuselage cavity to enclose all of the landing gears and bombs therein. In this respect, enclosure of all of the landing gears and bombs solely through the cavity-enclosing door may minimize the radar signature emission from the fuselage.
More specifically, the cavity-enclosing door may be hingeably or pivotally engaged to the lower fuselage portion of the fuselage. Such cavity-enclosing door has an outer door surface, whereas the fuselage has an outer fuselage surface. The outer door surface and the outer fuselage surface may be substantially flush with each other when the stowed position is formed. At least the outer fuselage surface and the outer door edges of the cavity-enclosing door should be substantially flush with each other when such position is formed.
In the present invention, the cavity-enclosing door may transition between the stowed position and a deployed position with respect to the internal fuselage cavity. This mobility of the cavity-enclosing door allows selective accessing of the landing gears and bombs from the internal fuselage cavity. In particular, the landing gears may be attached within the internal fuselage cavity in a manner as to retract in the stowed position and extend in the deployed position. In the preferred embodiment, the landing gears comprise a front landing gear and at least two back landing gears.
Moreover, the bombs may be releasibly attached within the internal fuselage cavity. By this attachment, the bombs can then be dropped from the internal fuselage cavity when the cavity-enclosing door opens. Smart bombs, such as global positioning system (GPS) guided bombs, may be utilized with the present invention. However, one of ordinary skill in the art will appreciate that other types, such as dumb bombs, may be used instead. As to one positional arrangement, each of the bombs may be selectively positioned between the landing gears. However, it should be recognized that other positional arrangements are readily available.
In addition, missiles may be releasibly attached to the inner door surface of the cavity-enclosing door. A person of ordinary skilled in the art will realize that a variety types of missiles, such as side winders or sparrows for example, can be used. Although the cavity-enclosing door may solely alternate between the stowed and deployed positions, it may further be adapted to be continuously positionable at any one of a number of positions lying therebetween. The missiles may be launched, either separately or collectively, at any one of these number of positions. The missiles may be enclosed with the landing gears and the bombs in the internal fuselage cavity when the cavity-enclosing door closes.
In accordance with the present invention, the cavity-enclosing door may comprise first and second door members. These door members may be jointly configured to form the stowed and deployed positions relative to the internal fuselage cavity. Notably, the first and second door members may converge toward one another when forming the stowed position. When forming the deployed position, they may diverge away from each other. The first and second door members may each have an outer centerline door edge. These outer centerline door edges may be immediately adjacent to each other when the stowed position is formed. Such edges may also simultaneously form a substantial flush relationship.